Chapter 10 - Installing the ACME screws

Materials needed to install lead screws. Admittedly this is a short chapter compared to the last, but it marks a point where I feel the machine is getting close to looking and soon to be running like it should.  As always, here is a picture of the parts required to install the lead screws.

Installing the Z-Axis Lead Screw

Lead screw installed on the Z-Axis. Lead screw installed on the Z-Axis. Just like the book, I started with the lead screw installation on the Z-Axis.  Well, let's just say that it didn't quite go off without a hitch.  When I run the screw down to the first nut, it threaded just fine, but going into the second wasn't so easy.  Even with the spacers I made for the Z-Carriage, I still didn't have enough clearance on the Z-Beam.  I mean it was close, the nut just barely rubbed the Z-Beam.  Still it was unacceptable.  So, I got out the callipers and went through a bunch of 3/8" washers until I found four that were the same size.  I added one to each carriage bearing to give me a little more clearance between the nuts and beam.  Next, I didn't really have enough wiggle room on the bottom nut to prevent it from binding when I run the lead screw into it.  To remedy this, I removed the 5/16" socket head screws and replaced them with 1/4-20 x 1" long bolts as recommended in the book.  After all that, I finally had enough room to shift things around and line up the lead screw.  WHEW, hope the rest are not that bad!!!

Installing the X-Axis Lead Screw

X-Axis lead screw installed. Next came the X-Axis lead screw.  The anti-backlash nuts on the X-Axis are held on by 1/4-20 x 1" bolts as per the plan because of the extrusion.  This lead screw installed with no problems at all.

Installing the Y-Axis Lead Screws

Y-Axis lead screws installed. When I built the Y-Carriages I used the supplied 5/16" socket head cap screws that came with the anti-backlash nuts.  After the issues with the Z-Axis, I went ahead and replaced them with the 1/4-20 x 1" bolts before I even started on the lead screw installation.  Also, Zachary and I found it helpful to grind down part of the head of the inside motor mount bolts to give a little more clearance for the opposite nut that attached the angle down to the extrusion.  This is a tight fit there.  Otherwise the Y-Axis lead screws installed just fine.

The machine in its current state

The KRMx01 CNC after installing the lead screws. The KRMx01 CNC after installing the lead screws. The machine is coming along just fine and I will be starting the electronics portion soon.  I think I will turn my attention to the computer rack that will be built into the table next.  I have put it off long enough.  See you in the next chapter.